In a magnetic recording and reproducing apparatus, a magnetic tape is placed and adapted to travel on the outer periphery of a tape guide drum equipped with rotary magnetic heads, for recording image signals or similar information signals or reproducing image signals already recorded on the magnetic tape. When the tape is placed on its preset route, it is folded intricately by the aid of tape guides and placed about the periphery of the tape guide drum over an angular extent of more than 180 degrees. Thus, when left for prolonged time in the loaded state, that is, as it is partially coiled about the tape guide drum and placed on the preset tape route, it can be easily adhered to the tape guide drum surface.
The conventional magnetic recording and reproducing apparatus of the type described above is usually so constructed that, when the magnetic tape is pulled back from its loaded state towards the tape mounting section (tape unloading operation), tape guide means such as tension regulator for extending and placing the magnetic tape on the preset tape route or the loading ring adapted for placing the tape around the tape guide drum may be rotated or shifted in unison.
In the above described apparatus in which the tape guide means such as tension regulator and loading ring are actuated in unison for unloading the magnetic tape from the extended, or loaded position, should the tape have become adhered to the tape guide drum surface, as mentioned hereinabove, the unloading operation is terminated while the tape is still left in the tape route and is not taken up or withdrawn into the tape cassette. Should the tape cassette be taken out of the cassette mounting section in this state, the tape may be injured or occasionally severed.
On the other hand, the loading unit or mechanism of the above described apparatus for pulling out the magnetic tape from the tape cassette and placing it on the tape route around the tape guide drum provided with rotary magnetic heads is so constructed and arranged that the loading ring adapted for guiding the tape for placing it about the tape guide drum is driven in rotation by a driving electric motor, while a tension regulator associated with the travelling tape for placing a preset tension on the tape as a function of the selected operating mode is driven by an active element such as solenoid plunger separate from the driving electric motor.
Since the prior-art apparatus makes use of plural driving devices such as a driving electric motor or a solenoid plunger for driving a loading mechanism adapted for placing the tape along the preset tape route, a mounting space is required for at least plural driving devices which makes it difficult to reduce the overall size of the apparatus. In addition, since the magnetic tape is loaded by plural driving devices, means must be provided for operatively coordinating the respective driving devices, which complicates the mechanism and further makes it difficult to reduce the overall size of the apparatus.
The loading ring employed in the above described prior-art magnetic recording and reproducing apparatus is connected to the driving shaft of the driving electric motor via a connection gearing in such a manner that the driving force developed in the electric motor is transmitted to the loading ring.
In the magnetic recording and reproducing apparatus, it is also known to have the loading ring mounted at an angle with respect to the chassis plate for further reducing the size of the apparatus. In order that the loading ring thus inclined with respect to the chassis plate may be connected to the connection gearing having its supporting shaft erected upright on the chassis plate, it is necessary that a bevel gear inclined at an angle equal to the mounting angle be provided to the outer periphery of the loading ring and also that another bevel gear be provided to the connection gearing for meshing with the firstly mentioned bevel gear. However, it is extremely difficult to get the bevel gear accurately machined in the large-sized loading ring which is placed around the tape winding guide drum and which is provided with a guide for guiding the magnetic tape. It is therefore difficult to have the loading ring properly meshing with the bevel gear constituting the connection gearing and to provide for smooth and accurate revolution of the loading ring.
Thus the present invention contemplates to provide a magnetic recording and reproducing apparatus which is so designed that, should the magnetic tape have become adhered to the tape guide drum, the tape can be released positively from the tape guide drum without injury to the tape thus providing for safe unloading of the magnetic tape.
The present invention also contemplates to provide a magnetic recording and reproducing apparatus which makes possible further reduction in size of the apparatus through reducing the number of the driving members performing the tape unloading operation.
The present invention also contemplates to provide a magnetic recording and reproducing apparatus which makes use of a folding guide unit or mechanism as means for pulling out and guiding the magnetic tape from the tape cassette mounting section towards the tape guide drum so as to enable the tape to be pulled out to a distant point by a small-sized mechanism thereby making possible further reduction in the size of the apparatus.
The present invention also contemplates to provide a magnetic recording and reproducing apparatus which provides for precise and simple connection between the loading ring inclined with respect to the mounting plane of the chassis plate and connection gearing means adapted for transmitting the torque of the driving electric motor to the loading ring, for thereby dispensing with special machining operation of the loading ring and reducing the space of the apparatus.